This is a reference, not medical advice. Before combining any herb with another herb, a supplement, or a medication, consult a qualified practitioner and your pharmacist or physician.
The five safety/warning tags on 239 Chinese herbs.
- Drug interactions — documented interactions with medications, with a derived risk level and interaction type (blood thinners, blood sugar, liver metabolism, and more).
- Incompatible · 十八反 — the classical "Eighteen Incompatibilities": herb pairs that must not be combined.
- Antagonizes · 十九畏 — the "Nineteen Antagonisms": herb pairs that mutually blunt or counteract each other.
- Toxic / restricted — herbs that are toxic, or restricted/illegal in the United States, with a toxicity note.
- Endangered / illegal — substances from CITES-protected species (e.g. tiger, rhinoceros, pangolin, saiga antelope, seahorse) that are illegal and must be replaced with humane, legal substitutes.
These flags describe what we document; the interaction risk level is not a clinical severity score. Always read a herb's full page and confirm with a qualified practitioner and pharmacist.
Showing 29 of 239 herbs with a safety flag.
- Bai Ji十八反 IncompatibleBletilla Rhizome (Rhizoma Bletillae)
- Bai Lian十八反 IncompatibleAmpelopsis, Japanese Ampelopsis Root (Radix Ampelopsis)
- Bai ShaoModerate interaction十八反 IncompatibleWhite Peony Root (Radix Albus Paeoniae Lactiflorae)Immune / Transplant
Separately, clinical trials of Total Glucosides of Paeony (TGP) — a standardized paeoniflorin-rich extract from the same Paeonia lactiflora root — combined with the conventional DMARDs methotrexate and/or leflunomide for active…
Incompatible with 十八反: Li Lu
- Ban XiaHigher interaction十八反 IncompatibleToxic / restrictedPinellia Rhizome (Rhizoma Pinelliae Tematae)Toxic / Restricted Herb
A cardiotoxicity signal is documented only for the RAW, unprocessed rhizome in an animal model (PMID 27698376) — not for the processed forms (Fa/Jiang/Qing Ban Xia) used clinically — but it is a reasonable basis for practitioner…
Incompatible with 十八反: Fu Zi, Cao Wu, Chuan Wu
Toxicity: Yes — raw Ban Xia (Sheng Ban Xia) is toxic and, per the legacy record, is used only externally; every internally-used form is one of the processed preparations that neutralize its irritant components before…
- Bei Sha Shen十八反 IncompatibleGlehnia Root (Radix Glehniae Littoralis)
Incompatible with 十八反: Li Lu
- Cao WuHigher interaction十八反 Incompatible十九畏 AntagonizesToxic / restrictedPrepared Wild Aconite (Radix Aconiti Kusnezoffii Preparata)Sedatives / CNSToxic / Restricted Herb
Given its narrow therapeutic window and potent cardioactive alkaloids, Cao Wu warrants particular caution alongside other drugs that affect the heart. Additive risk is plausible with antiarrhythmics, cardiac glycosides, and other…
Incompatible with 十八反: Bai Ji, Ban Xia, Chuan Bei Mu, Gua Lou, Gua Lou Pi, Gua Lou Ren, Tian Hua Fen, Zhe Bei Mu, Bai Lian
Antagonizes / antagonized by 十九畏: Xi Jiao
Toxicity: Extremely toxic — regarded as more toxic than Chuan Wu; use only the processed root, only under qualified supervision. The toxicity comes from diester diterpenoid alkaloids (aconitine, mesaconitine,…
- Chi ShaoModerate interaction十八反 IncompatibleRed Peony Root (Radix Rubrus Paeoniae Lactiflorae)Bleeding / Blood Thinners
Preclinical pharmacology supports caution. Compounds isolated from Paeonia lactiflora — including paeoniflorin — inhibited platelet aggregation and blood coagulation in vitro (PMID 20824965). This is a theoretical basis for additive…
Incompatible with 十八反: Li Lu
- Chuan Bei Mu十八反 IncompatibleEndangeredTendrilled Fritillaria Bulb (Bulbus Fritillariae Cirrhosae)
- Chuan WuHigher interaction十八反 Incompatible十九畏 AntagonizesToxic / restrictedPrepared Sichuan Aconite (Radix Aconiti Preparata)Sedatives / CNSToxic / Restricted Herb
Because of its narrow therapeutic window and cardioactive alkaloids, Chuan Wu warrants particular caution alongside other drugs that affect the heart. Additive risk is plausible with antiarrhythmics, cardiac glycosides, and other…
Incompatible with 十八反: Bai Ji, Ban Xia, Chuan Bei Mu, Gua Lou, Gua Lou Pi, Gua Lou Ren, Tian Hua Fen, Zhe Bei Mu, Bai Lian
Antagonizes / antagonized by 十九畏: Xi Jiao
Toxicity: Extremely toxic — use only the processed root, only under qualified supervision. The toxicity comes from diester diterpenoid alkaloids (aconitine, mesaconitine, hypaconitine). Traditional processing —…
- Da Ji十八反 IncompatibleJapanese Thistle, Cirsium (Herba Cirsii Japonici)
Incompatible with 十八反: Gan Cao
- Dan ShenHigher interaction十八反 IncompatibleSalvia Root (Radix Salviae Miltiorrhizae)Bleeding / Blood ThinnersLiver Metabolism (CYP450)
Yes — Dan Shen has a well-documented interaction with warfarin: it decreases warfarin clearance and increases its bioavailability, potentiating anticoagulation and raising bleeding risk. This is one of the better-established herb–drug…
Incompatible with 十八反: Li Lu
- Dang Shen十八反 IncompatibleCodonopsis Root (Radix Codonopsitis Pilosulae)
Incompatible with 十八反: Li Lu
- Fu ZiHigher interaction十八反 IncompatibleToxic / restrictedProcessed Aconite (Radix Lateralis Praeparatus Aconiti Carmichaeli)Cardiac / Heart RhythmToxic / Restricted Herb
The primary documented concern is cardiac. The aconitine-type diester alkaloids are recognized in the pharmacology literature as cardiotoxic and arrhythmogenic, so reference sources flag added caution where cardiac or antiarrhythmic…
Incompatible with 十八反: Bai Ji, Ban Xia, Chuan Bei Mu, Gua Lou, Gua Lou Pi, Gua Lou Ren, Tian Hua Fen, Zhe Bei Mu, Bai Lian
Toxicity: Raw aconite is highly toxic, and Fu Zi is the detoxified, processed lateral root — only processed forms are used internally. Toxicity is attributed to the diester diterpenoid alkaloids (aconitine,…
- Gan CaoHigher interaction十八反 IncompatibleLicorice Root (Radix Glycyrrhizae)Cardiac / Heart RhythmDiuretics / Fluid Balance
Two interactions are commonly flagged: potentiation of corticosteroids, and increased cardiac-glycoside (e.g., digoxin) risk via potassium loss. Glycyrrhizin's inhibition of 11 -hydroxysteroid dehydrogenase type 2 slows cortisol…
Incompatible with 十八反: Da Ji, Jing Da Ji, Gan Sui, Hai Zao, Yuan Hua
- Gan SuiHigher interaction十八反 IncompatibleToxic / restrictedKansui Root (Radix Euphorbiae Kansui)Toxic / Restricted Herb
The best-characterised interaction is herb–herb rather than herb–drug: co-administration with licorice measurably reduced licorice-constituent bioavailability in rats and shifted the toxicity-efficacy balance unfavourably (see notes and…
Incompatible with 十八反: Gan Cao
Toxicity: High. Gan Sui is a documented irritant and hepatotoxin, and its toxicity comes from the same diterpene constituents that produce its purgative effect — the effect and the harm are not separable. A 2016…
- Gua Lou十八反 IncompatibleTrichosanthes Fruit (Fructus Trichosanthis Kirlowii)
- Gua Lou Pi十八反 IncompatibleTrichosanthes Peel, Snake Gourd Peel (Pericarpium Trichosanthis Kirlowii)
- Gua Lou Ren十八反 IncompatibleTrichosanthes Seeds (Semen Trichosanthis Kirlowii)
- Hai ZaoModerate interaction十八反 IncompatibleSeaweed, Sargassum (Herba Sargassii)Thyroid
Its iodine content is directly relevant to thyroid medications. Because thyroid hormone replacement and anti-thyroid medications are iodine-sensitive, and Hai Zao is an iodine-concentrated seaweed, practitioner awareness and monitoring…
Incompatible with 十八反: Gan Cao
- Jing Da JiHigher interaction十八反 IncompatibleToxic / restrictedPeking Spurge Root (Radix Euphorbiae Pekinensis)Toxic / Restricted Herb
The best-characterised interaction is herb–herb: the classical prohibition on combining it with Gan Cao (licorice, Radix Glycyrrhizae), one of the Eighteen Incompatibilities and a pair our own incompatibility records hold. What modern…
Incompatible with 十八反: Gan Cao
Toxicity: High, and mechanistically well characterised. The toxicity of Jing Da Ji and its purgative effect come from the same chemistry — the effect and the harm are not separable. Documented targets are the…
- Ku ShenModerate interaction十八反 IncompatibleSophora Root (Radix Sophorae Flavescentis)
Because concentrated matrine/oxymatrine preparations (including injectable Compound Kushen Injection, used in China as adjunctive cancer supportive care) are pharmacologically active and hepatically metabolized, practitioner awareness…
Incompatible with 十八反: Li Lu
- Li LuHigher interaction十八反 IncompatibleToxic / restrictedVeratrum Root and Rhizome (Radix Et Rhizoma Veratri)Blood PressureCardiac / Heart RhythmToxic / Restricted Herb
Because its toxic alkaloids act on cardiac sodium channels and produce vagally mediated bradycardia and hypotension, reference sources would reasonably flag added caution alongside antiarrhythmic medications, beta-blockers or other…
Incompatible with 十八反: Bai Shao, Bei Sha Shen, Chi Shao, Dan Shen, Dang Shen, Ku Shen, Ren Shen, Xi Xin, Xuan Shen, Sha Shen
Toxicity: Yes — Li Lu is classed as very toxic, and the site flags it accordingly. Its toxicity is attributed to steroidal ester alkaloids — principally veratramine and jervine (reported as the two largest fractions…
- Ren ShenModerate interaction十八反 Incompatible十九畏 AntagonizesGinseng Root (Radix Ginseng)
Two interactions have case-report or clinical-trial documentation; a third is a traditional-use guideline. MAOIs (e.g., phenelzine) — a published case report describes insomnia, headache, and tremulousness when ginseng was taken…
Incompatible with 十八反: Li Lu
Antagonizes / antagonized by 十九畏: Wu Ling Zhi
- Sha Shen十八反 IncompatibleAdenophora Root, Four Leaf Lady Bell Root (Glehniae/Adenophorae Radix)
Incompatible with 十八反: Li Lu
- Tian Hua FenModerate interaction十八反 IncompatibleToxic / restrictedTrichosanthes Root (Trichosanthis Kirlowii Radix)Toxic / Restricted Herb
The relevant safety literature concerns the purified, injectable protein trichosanthin, which has documented immune/hypersensitivity effects and was studied experimentally alongside antiretroviral therapy in HIV research in the early…
Incompatible with 十八反: Fu Zi, Cao Wu, Chuan Wu
Toxicity: Tian Hua Fen s pregnancy contraindication rests on trichosanthin, a ribosome-inactivating protein in the root that was purified and used clinically in China as an injectable to terminate pregnancy — animal…
- Xi Xin十八反 IncompatibleToxic / restrictedChinese Wild Ginger, Asarum (Herba Asari Cum Radice)
Incompatible with 十八反: Li Lu
Toxicity: Xi Xin carries real, well-documented toxicity concerns rather than being toxicologically inert. Asarum species contain aristolochic acid analogs (AAAs — nephrotoxic and IARC Group 1 carcinogens) and…
- Xuan ShenModerate interaction十八反 IncompatibleNingpo Figwort Root (Radix Scrophulariae Ningpoensis)Blood Sugar
May interact with anti-diabetic medications. Xuan Shen has traditionally been flagged as potentially interfering with anti-diabetic drugs; patients on blood-glucose-lowering medication should have this checked by their practitioner and…
Incompatible with 十八反: Li Lu
- Yuan HuaHigher interaction十八反 IncompatibleToxic / restrictedGenkwa Flower (Flos Daphnis Genkwae)Bleeding / Blood ThinnersLiver Metabolism (CYP450)Toxic / Restricted Herb
There is experimental evidence that it can. In rats, genkwa decoction significantly increased the absorptive transport of rhodamine 123 — a standard marker substrate for the P-glycoprotein efflux transporter — across jejunum membranes,…
Incompatible with 十八反: Gan Cao
Toxicity: Yes — genuinely and specifically. The toxicity of Daphne genkwa comes from daphnane-type diterpenes, in particular the daphnane orthoesters, a compound class whose irritant and tumour-promoting relatives…
- Zhe Bei Mu十八反 IncompatibleThunberg Fritillaria Bulb (Fritillariae Thunbergii Bulbus)
Please read — this list is not complete
While we have made every effort to catalog herb interactions, incompatibilities, and toxicities, these are deep, complex, and still-developing fields. These lists cannot be exhaustive. Cautions beyond those documented here undoubtedly exist, new ones are reported as research advances, and a herb's absence from a list is not evidence that it is safe. Treat this as a starting point for a conversation with a qualified practitioner, pharmacist, or physician — never as a final clearance.
For how we research, cross-reference, and grade the evidence behind these entries, see How we source our content .